Silica/modified poly(vinyl alcohol) (PVA) organic-inorganic hybrid gas barrier films were prepared by sol-gel method using silicon alkoxides and modified PVA on polypropylene (CPP) substrates. Oxygen permeances through the films were measured by a variable-pressure method. Oxygen permeability coefficient of the hybrid was one order lower than those of poly(vinylidene chloride) (PVDC) and water vapor transmission rate of the hybrid was the same order of PVDC. Pencil hardnesses of the CPP with the hybrid films were more than 4B. These values were higher than that of CPP (6B). These properties were thought to be due to well dispersion of inorganic segments (silica) and organic segments (modified PVA) at molecular level in the hybrid.

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